Raw is data straight frm the sensor (the only processing done is signal amplification to adjust the ISO) and so contains everything. It's usually 12 or 14 bits in depth (every extra bit doubles the number of different tonal values available for processing). It's not a viewable file, and requires processing to make it so.

Jpg is a processed file, with adjustments for white balance, sharpening, contrast and saturation made for you. It's 8 bits, and a lossy format (meaning that it's compressed and the compression loses some fine detail - every time you change and save it.

Jpgs are smaller and therefore faster to write to the card in the camera (and transfer to the computer). They are more convenient as they are "finished" files. The downside is the lack of scope for later adjustments, and the data loss that has already occurred. If you get the exposure wrong, you've more data to enable a recovery from a raw file - at least a stop of overexposure headroom to help you compared to a jpg.

If you're a black and white photographer, you should find that the lack of tones inhherent in an 8 bit file scuppers your ability to produce a print with the best possible tonal range.

For a person of my age and background, it's the difference between getting a negative back from the corner chemist that you can take into your darkroom and making exactly the print you want and the standard print that comes back with the processed film.

jpgs are compressed to reduce the file size. To do this the algorithm discards lots of information from the file. If you open a jpg and make an adjustment then save it the algorithm is re-applied to the file and even more information will be discarded. This will result in the image gradually deteriorating until eventually it will be un-useable.

Your camera will also apply a fixed amount of contrast, sharpening, brightness and saturation to every image regardless of the lighting conditions or what you want the image to look like.

RAW files have a huge advantage over any other file type in that you can change the exposure (not brightness) and white balance AFTER you have taken your picture.

RAW files are like digital negatives. A pure record with nothing applied to it. Like a negative, RAW files need a two stage process. So stage one is to use a RAW converter to apply the changes that you want (not what the camera wants) to contrast, saturation, sharpness and exposure. Now the really good thing about RAW files is that these changes are not made to the actual RAW file. This will remain totally unchanged so that in the future you can return to the original file and re-process it in a completely different way if you want to. The changes you make are stored in a sidecar file which holds your changes and simply applies these to the RAW file when you open it.

So now you have applied the changes that you want to your RAW file you can save it as any image file that you want. For web use jpg is the obvious choice, but you can also save as a tiff, PNG or PSD file. These do not deteriorate every time you tweak and save them so are good for storage - albeit they are bigger files than , but storage is very cheap these days.

If you want to do further editing to your image that you cannot do in the RAW converter - such as cloning, or anything to do with layers, you open the image in your editing programme directly from the RAW converter, do your editing then save it in the format of your choice. I will usually save a jpg for web/device and also as a tiff for storage.

Once you have settled into the routine you will never go back to jpg. My last three cameras over the last ten years have never taken a jpg.

Stephen and Graham - thanks for your info/comments on raw files, but I'm still confused!!

Where does the raw converter fit in?

The RAW converter is the first stage of processing where you can make your initial adjustments. Depending on the pictures and their intended use, this might be all the processing you will need and you can export straight to jpg.

Quote:

Originally Posted by doc.

When I shoot raw plus jpeg and view images in say Nikon software I see very little, if any difference.
(maybe because they are so bad!!)

I suspect the Nikon software is using the default settings which will replicate the camera's jpg settings thus producing the same image.

Quote:

Originally Posted by doc.

I would be very grateful if either or both of you would describe (idiots guide please!!) your workflow.

For me - take pictures - put them onto computer using Lightroom - use LR to make initial adjustments - then either export jpgs or export 16bit tiffs for further editing in Photoshop then save as 8bit tiffs. If I want jpgs from any or all of these I use an action to produce them.

Quote:

Originally Posted by doc.

I thought making adjustments to raw then convert to jpeg or whatever - don't understand use of separate raw converter.

Thanks, John

If you are using Adobe Camera RAW in Elements or Photoshop, this is a RAW converter. Unlike LR (or Bridge) you can only deal with one image at a time and as I don't use this method I am unsure if you can directly export or have to go through Elements or Photoshop depending on what one you are using.

I think Graham has covered it all. At least some raw files have the jpg that either would have been or was produced in camera embedded to let it be easily viewed. You'll always get a jpg somewhere from the camera, since that is what is shown on the rear screen and is the basis for the histogram. Some camera maker's raw software uses the in camera settings to replicate the jpg as a starting point, so initially there should be little if any difference.

My own workflow is actually irrelevant to you, since I start with film. I scan and save the raw scanner data (my software lets me do this) and I can then reprocess it without rescanning until I get the best possible scan (or the best I can be bothered to make). The scanner software is my raw converter. I then produce a 16 bit tiff file for Photoshop and stay in 16 bit mode unless I want a jpg to post somewhere.

My digital camera use is confined to snapshots or those photographs which are destined to appear on the internet (I produce the web site for Friends of Hove Park), and usually I'm not sufficently bothered to use anything other than the jpg produced by the camera. There are a very few occasions when I have wanted to make adjustments (usually confined to specialised usage like slide copying in camera) and I then use DXO and once again save as 16 bit tiff.

Any editing is done in Photoshop CS2 and the files, as stated, remain as 16 bit tiff files. It might be worth mentioning that the film I use is black and white, which does have a bearing on my determination to avoid 8 bits, because 8 bits aren't enough for B&W.

came to this ready to write a long reply but Stephen and Graham have pretty much covered it all. (thankfully - as they are much better in putting it into words than I am). One thing i find confuses people is why you can view it on your screen on your camera and it looks beautiful and not at all like the image you might see once you have uploaded it into a converter on your computer, just like when you make changes your computer saves than as separate file , your camera makes a tiny jpg that allows you to view your image but this JPG is set to the settings that your camera would have applied had you shot the image in RAW, which is one reason why i dont use the histogram on my camera as it will give you the readings from the small JPG file NOT the RAW image.

Raw is data straight frm the sensor (the only processing done is signal amplification to adjust the ISO) and so contains everything. It's usually 12 or 14 bits in depth (every extra bit doubles the number of different tonal values available for processing). It's not a viewable file, and requires processing to make it so.

Jpg is a processed file, with adjustments for white balance, sharpening, contrast and saturation made for you. It's 8 bits, and a lossy format (meaning that it's compressed and the compression loses some fine detail - every time you change and save it.

Jpgs are smaller and therefore faster to write to the card in the camera (and transfer to the computer). They are more convenient as they are "finished" files. The downside is the lack of scope for later adjustments, and the data loss that has already occurred. If you get the exposure wrong, you've more data to enable a recovery from a raw file - at least a stop of overexposure headroom to help you compared to a jpg.

If you're a black and white photographer, you should find that the lack of tones inhherent in an 8 bit file scuppers your ability to produce a print with the best possible tonal range.

For a person of my age and background, it's the difference between getting a negative back from the corner chemist that you can take into your darkroom and making exactly the print you want and the standard print that comes back with the processed film.

You have explained the whole idea in such a clear way, thank you for this.

Thank you all for the insightful idea about both the RAW and JPG format here. Its easy to find the difference in internet but getting know about the things from people's own experience is always far better.